Commutator



Allg. 23, 1938. R F CARTY 2,127,549

I COMMUTATOR Filed May 6, 1955 INVENTOR.

Patented Aug. 23, 1938 UNITED STATES PATENT ,OFFICE 4 Claims.

r The present invention relates to improvements in commutators for electrical motors or generators and its principal object is to provide a commutator of superior construction that is comparatively easy to assemble, has the greatest strength where it is needed most and can be constructed with the least waste of material and at the greatest economy.

More particularly it is proposed in the present invention to provide a novel commutator segment which is especially strong at the ends and has the greatest radial thickness at the ends.

It is further proposed to, provide a method of making the novel segment in a very simple man- I l5 ner and without any waste of material.

It is further proposed to provide a novel means of securing the segments to a hub structure and a novel method for assembling the segments and the hub structure into a unit.

Further and other objects of the invention will appear as the specification proceeds.

The preferred, form of my invention is illustrated in the accompanying drawing in which Fig. 1 shows an end view of my commutator,

Fig. 2, an axial section taken along line 2-2 of Fig. 1,

Fig. 3, an end view of a hub section used in my commutator,

Fig. 4, an axial section through the same,

Fig. 5, a longitudinal section through an expansion ring,

Fig. 6, a plan view of the same, V

Fig. '7, a plan view showing the ring in expanded form,

Fig. 8, an agial section showing the hub sec- .tions and the expansion' ring in their assembled relation prior to the application of the commutator segments,

A Fig. 9 is a plan view illustrating one of the 40 blanks or bars to be formed into a segment.

Fig. l0 is a side elevation of one of the blanks, another step in the formation of the segments, Fig. l1 is an end view thereof, Fig. 12 is still another side view, showing one of the segments 45 during its formative stage, Fig. 13 is a side elevation of one of the completed segments; and Fig. .14 is an end view thereof as shown in Fig. 13.

While I have shown only the preferred form of my invention Iwish to have it understood that 50 various changes and modications may be made within the scope of the claims hereto attached without departing from the spirit of the invention. I

In its preferred form my commutator segment 55 I is made asfshown in Fig. 10, that is in the the flanges.

(Cl. P11-321) form of a bar 2 having tangs 3 projecting centerwise from the ends thereof, the tangs being in the same plane so as to confront one another and to define a recess 4 between the same. The tangs are tapered in their confronting faces as shown at 5 so that when the segments are arranged in the conventional annular series of a lcommutator the recesses define an annular groove with undercut sides.

The longitudinal sides of the segment are tal pered radially in conventional form as shown at 6 and are preferably roughened and one outer edge of the segment has a slight projection 'i and is split longitudinally as at 8 to receive a connecting wire (not shown). 15

My segment is preferably made in the manner illustrated in Fig. 9. A bar 9 of suflcient length and material to make one segment is flattened to be about twice as wide as it is thick and is bent over into hair pin form whereupon 20 the two legs of the hair pin are rmly pressed upon one another so that the result is a bar onehalf the length and twice the thickness of the original bar, substantially square in cross-section. The bar isbent again transversely near its ends 25 as shown at I0 so as to present a middle section I I and two projections I2.

For assembling the segmentsinto a commutator I utilize two hub sections 22, one of which is shown in detail in Figs. 3 and 4, and an ex- 30 pansion ring 23 illustrated in detail in Figures 5-7. -Each hub section comprises a tubular portion 24, a conical flange 25 flaring outwardly from one end thereof and a reversed conical extension 26 projecting from the end of the flange. The ring 23 35 is of substantial thickness, round in section and is split, preferably on a taper, so as to be expansible, and thus forcing the flanges 25 and extensions 26 outwardly.

In assembling the commutator the two hub sections are placed together in the manner shown in Figure 8, with the ends of the iianges 25 toucning and the expansible ring 23 disposed between When the hub sections are thus arranged the two extensions ilare away from one another but the extreme edges are sufficiently close to allow the segments to be placed over the extensions with a tilting movement so that the angesare accomodated in the recesses 4 of the segments. Before the segments are applied a suitable insulating layer 28 is placed over each extension 26 and then the segments are positioned in alternating succession with similarly formed vlayers of mica or other insulating material.

After all the segments have been applied the ring 23 is expanded by the use of a suitable tool such as a drift 'taper punch and the expanding ring forces the two hub sections apart and crowds the conical extensions 28 into the undercut sides of the annular groove formed by the recesses 4 of the segments, thereby firmly interlocking the segments with the hub sections. Suitable insulating rings are provided between the hub structures and the segment assembly as in the rings 29 and 30 and a closure 3| made of steel or fiber and introduced between the ring 30 and the hub finishes the assembly.

I clairn:

1. A commutator comprising an annular series of segments having tangs projecting center-wise from the ends thereof, the tangs being tapered to define an annular groove with undercuts in the sides thereof, a pair of hub rings having reversely tapered extensions projecting into the undercuts, and a resilient ring tending to urge the extensions into the undercuts for effecting a firm bond'between the rings and the segments.

2. A commutator comprising an annular series of segments having tangs projecting center-wise from the ends thereof, the tangs being tapered to define an annular groove with undercuts in the sides thereof, a pair of hub rings having confronting tapered flanges with reversely tapered extensions projecting into the grooves, and a split ring active radially on said flanges and when expanded tending to urge the extensions into the undercuts.

3. A commutator. comprising an annular series of segments having tangs projecting center-wise from the ends thereof, the tangs being tapered `to define an annular groove with undercut sides and means in gripping engagement with the undercut sides for holding the'segrnents in assembled relation comprising, a pair of hub rings having confronting tapered flanges with reversely arranged extensions, and a split expanding ring active radially on said flanges and capable of urging the extensions into said undercuts when said ring is expanded.

4. A commutator comprising an annular series of segments having tangs projecting center-wisc from the ends thereof, the tangs being tapered to define an annular groove with undercut sides andl means in gripping engagement with the undercut sides for holding the segments in assembled relation comprising, a pair of hub rings having confronting tapered flanges with reversely arranged extensions, and a split expanding ring active radially on said flanges and capable of urging the extensions into said undercuts when said ring is expanded, said expanding ring being split diagonally and capable of being expanded.

ROY F'. CARTY 

